Genetic Control of Enzyme Structure"^ 



SiGMUND R. SusKiND " and Charles Yanofsky ^ 



Introduction 



Some of the basic concepts for our present-day understanding of 

 the gene-enzyme relationship were formulated by Garrod in the 

 early 1900's, on the basis of studies of human inborn errors of me- 

 tabolism (Garrod, 1923). These concepts were further developed 

 and experimentally supported by Beadle, Ephrussi, Tatum, and 

 others in studies with eye color mutants of Drosophila and by other 

 workers in studies of anthocyanin formation in plants ( Wagner and 

 Mitchell, 1955). It was because of the difficulties in performing 

 biochemical studies with existing material that studies with the 

 ascomycete, Neiirospom crassa, were begun by Beadle, Tatum, and 

 their co-workers. These studies as well as later investigations with 

 Escherichia coli and other microorganisms led to the elucidation of 

 numerous biosynthetic pathways. More important, from a genetic 

 standpoint, they offered repeated confirmation of a basic relationship 

 between gene, biochemical reaction, and the enzyme catalyzing the 

 reaction. As you know, this relationship formed the basis for the 

 "one gene and one enzyme" hypothesis which was developed and 

 expanded by Beadle, Tatum, Bonner, Horowitz, and others ( Beadle, 

 1959; Tatum, 1959). It is this relationship of gene to enzyme that 

 we wish to discuss, particularly with regard to the problem of genetic 

 control of enzyme structure. 



1 Research supported by the United States Pubhc Health Service and the National 

 Science Foundation. 



2 The McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland. 

 ^ Department of Biological Sciences, Stanford University, Stanford, California. 



